As illustrated by the charged container 100 shown in FIG. 19, a widely used charged container wherein a sealant for construction, or the like, is charged into a container, is one comprising a hard cylindrical container main body 103, which has an discharge hole 102 for discharging the sealant 101 formed at the front end portion thereof and which is open at the other distal end portion thereof, and a plunger 104 inserted inside the distal end portion of the container main body 103. In this charged container 100, a composition is adopted whereby, after releasing a lid 105 for closing the discharge hole 102 and cutting open a virgin film 106, a nozzle (not illustrated) is fitted to the discharge hole 102, the container is set in a special discharge gun and by operating a lever of the discharge gun, the plunger 104 is caused to move towards the front end side of the container main body 103, so that the sealant is extruded and discharged from the nozzle of the discharge hole 102.
In a charged container 100 having a composition of this kind, since it is possible to expel practically all of the air between the plunger 104 and the sealant 101, externally, and since the airtightness between the plunger 104 and the container main body 103 can be guaranteed satisfactorily, so that is widely used at present, but since the container main body 103 is rigid, it is not possible to compress the container main body 103 to a small size after all of the sealant 101 has been discharged, and hence there are limits on the volume reduction of the container main body 103 and a problem arises in that the volume of the waste material is very large.
Consequently, a flexible container has been proposed, in Japanese Patent Laid-open No.(Hei)7-171461, for example, which comprises an intermediate cylindrical section made from a flexible film, and a relatively hard upper moulding section and lower moulding section provided integrally with the front end portion and the other distal end portion of the intermediate cylindrical section. By setting a container in which the sealant is charged into this flexible container, on the outer tube of a discharge gun, and then moving the lower moulding section towards the upper moulding section, the sealant can be extruded and discharged from a nozzle of the discharge hole formed in the upper moulding section, whilst crushing the intermediate cylindrical section, and therefore, after the sealant 101 has been squeezed completely, the flexible container will be in a small size, thereby enabling to reduce the volume of the waste material.
Moreover, the abovementioned patent discloses a moulding method using insert injection mould as a method for manufacturing a flexible container wherein, firstly, the film is rolled on the mandrel and fabricated into an intermediate cylindrical section which is open at both ends, whereupon it is set in the mould of an insert injection moulding equipment which is formed with circumference moulding spaces at positions corresponding to the lower moulding section and the upper moulding section, and a synthetic resin is injected into the circumference moulding spaces, thereby forming the upper moulding section and the lower moulding section integrally with both ends of the intermediate cylindrical section.
However, the aforementioned moulding method using insert injection mould involves problems in that: it requires expensive injection moulding equipment; in setting the intermediate cylindrical section in the mould, a large mould is required, and the productivity are low compared to the large size of the mould equipment; and in the case of containers having the same diameter but different capacity (length), different moulds are required. For the manufacturer of the containers, the lower the productivity, the greater the price of the equipment.